N-methylolsilylethers of melamines



United States Patent Oifice 3,546,223 Patented Dec. 8, 1970 3,546,223N-METHYLOLSILYLETHERS OF MELAMINES Ferdinand Senge, Krefeld, and HermannSchnell, Krefeld- Urdingen, Germany, assignors to Farbenfabriken BayerAktiengesellschaft, Leverkusen, Germany, a corporation of Germany NoDrawing. Original application July 11, 1967, Ser. No. 652,413. Dividedand this application June 30, 1969, Ser. No. 837,920

Claims priority, application Ggrmany, July 26, 1966,

US. Cl. 260-2496 6 Claims ABSTRACT OF THE DISCLOSUREN-methylolsilylethers formed by reacting N-methylol compounds withhexalkyldisilazanes in a molar ratio of about 1:1 to 1:8 at temperaturesof 20-130 C. and their utility in modifying polymeric products.

CROSS-REFERENCE TO RELATED APPLICATION This application is a division ofapplication Ser. No. 652,413 as filed July 11, 1967.

This invention relates to N-methylolsilylethers and to a process fortheir preparation.

N-methylolsilylethers have not hitherto been known. A process for thepreparation of N-methylolsilylethers has now been found which comprisesreacting N-methylol compounds with hexalkyldisilazanes in a molar ratioof about 1:1 to 1:8 at temperatures of 20130 C.

The reaction may be explained by the following equation:

R =H alkyl or aryl It is surprising that the process according to theinvention proceeds in such a simple manner and with good yields.

The N-methylol compounds (I) used as starting materials are known fromthe literature and can be obtained by reacting suitablenitrogen-containing compounds with formaldehyde in an aqueous medium orwith polymeric formaldehyde in an anhydrous medium.

The following compounds may be mentioned as examples of suitableN-methylol compounds for the process of the invention: N-methylolcompounds of aliphatic, aromatic, cycloaliphatic, araliphatic,heterocyclic carboxylic or sulphonic acid amides or carboxylic acidimides. The carboxylic acid or sulphonic acid amides may be substitutedon the amide group by alkyl groups having 1 to 8 C-atoms such as methyl,ethyl or isopropyl or by aryl groups such as phenyl or naphthyl, andthese may in addition contain lower alkyl or halogen substituents.Similarly, the acid radicals on which the carboxylic acid or sulphonicacid amides are based may be substituted by radicals such as halogen, inparticular chlorine, or by nitro groups, alkoxy groups or alkoxycarbonyl groups etc. The above mentioned aliphatic or araliphatic acidamides or imides may be linear or branched; they may also containolefinically unsautrated bonds once or a number of times in themolecule. The carboxylic acid and sulphonic acid amides and carboxylicacid imides are derived from the corresponding monoor polybasic acids.

The following are examples of typical N-methylol compoundsN-methylol-acetamide, N-methylol-propionic acid amide,N-methylol-N-methylpropionic acid amide, N- methylol-undecanoic acidamide, N-methylol-stearic acid amide, N-methylol-palmitic acid amide,N-methylol-achloroacetamide, N-methylol-acrylic acid amide,N-methylol-N-phenyl acrylic acid amide, N methylol-methacrylic acidamide, N-methylol-a-ethyl acrylic acid amide, N-methylol-a-chloroacrylicacid amide, N-methylol-oleic acid amide, N-methylol-sorbic acid amide,N,N-bismethylol-fumaric acid diamide, N,N'-bis-methylol-muconic aciddiamide, N,N-bis-methylol-adipic acid diamide andN,N'-bis-methylol-sebacic acid diamide; N-methylolcyclo-hexanecarboxylicacid amide, N-methylol-cyclopentane-carboxylic acid amide;

N-methylol-benzoic acid amide; N-methylol-p-tolyl acid amide,N-methylol-naphthoic acid amide, N-methylolsalicylic acid amide,N-methylol-4-hydroxybenzoic acid amide, N-methylol-4-tertiary butylbenzoic acid amide, N-methylol-4-chlorobenzoic acid amide,N-methylolphenylacetic acid amide and N-methylol-4-pyridino-carboxylicacid amide; N-methylol-methanesulphonic acid amide,N-methylol-butane-sulphonic acid amide, N-rnethylol-dodecylsulphonicacid amide, N-methylol-benzene sulphonic acid amide,N-methylol-N-methyltoluenesulphonic acid amide, andN-methylol-cyclohexanesulphonic acid amide;

N-methylol-malonic acid imide, N-methylol-rnaleic acid imide,N-methylol-phthalimide, N-methylol-tetrahydrophthalimide,N-methylol-hexahydrophthalimide and N- methylol-diglycollic acid imide.

Other suitable N-methylol compounds are saturated or unsaturatedurethanes or ureas or N-monomethylol to N-hexamethylol compounds ofmelamine. The said classes of compounds may be partly substituted on thenitrogen by alkyl groups having 1 to 4 C-atoms or alkenyl groups having2 to 6 C-atoms or by the butadiene-(1,3-)-yl group.

The following compounds may be mentioned as particular examples:N-methylol-carbamic acid esters having 1 to 18 C-atoms in the esteralkyl group, N-methylol-carbamic acid allyl esters (allylurethane),N-monomethylolurea, N,N-bis-methylol-urea,N-monomethyl-N-monomethylolurea, N,N-dimethyl-N-monomethylol-urea, N,N-dimethylol N,N' dimethyl-urea, N-mononmethylolethylene-urea,N,N-bis-methylol-ethylene-urea, N-vinyl- N-methylol-urea, andN-rnethylol compounds of dicyandiamide.

The following compounds are preferred: N-methylolacetamideN-methylol-acrylic acid amide, N-methylolmethacrylic acid amide,N-methylol-p-toluenesulphonic acid amide, N-methylolsorbic acid amide,N-rnethylol-maleic acid amide, N-methylol-phthalic acid imide,N-methylolcarbamic acid allyl esters, N-monomethylolurea, N,N-bis-methylol-urea and the monoto hexamethylol compounds of melamine.

The hexaalkyl-disilazane to be used according to the invention whichhave the general formula in which R:alky1, preferably methyl, R ==H oralkyl having 1 to 18 C-atoms, aryl such as phenyl, which may besubstituted by halogen, in particular chlorine or by alkyl groups 1 to 4C-atoms, are obtained in known obtained in known manner (see W. NollChemie und Technologie der Silikone, Verlag Chemie G.m.b.H., Weinheim,Bergstr. 1960, p. 75; Gmelins Handbuch der Anorg. Chemie, Verlag ChemieG.m.b.H., 1958, 8th Edition, volume 15, Part C, p. 307) by reactingtrialkylmonocholorsilanes with ammonia or primary aliphatic or primaryaromatic amines.

It is preferred to use hexamethyldisilazane,N-methylhexamethyldisilazane and N-ethyl hexamethyldisilazane.Hexamethyldisilazane is the most preferred compound.

The N-methylol compounds are reacted with the disilazanes in the molarratio of about 1: 1 to 1:8, preferably 111.1 to 1:2 at temperatures of20 to 130 C., preferably 40 to 80 C. It is advantageous to carry out thereaction in the presence of catalytic quantities of a catalyst which hasan acid action. The quantities of catalyst are from 0.001 to 2% byweight based on disilazane, preferably 0.01 to 0.5% by weight.

The following compounds are examples of suitable acid catalysts: HCl, H50 H PO butanesulphonic acid, ptoluene-sulphonic acid and, preferably,the corresponding ammonium salts.

With very highly reactive N-methylol compounds, the reaction can also becarried out without catalysts although the reaction then generallyproceeds considerably more slowly and only at higher temperatures. Thismay lead to deleterious side reactions such as autocondensation of themethylol compounds. In the case of compounds that are less sensitive tocondensation, one can also successfully use catalytic quantities of thefree acid.

The process according to the invention can be carried out in bulk or inan organic solvent. Suitable solvents include, for example,dimethylsulphoxide, methyl acetate, ethyl acetate, dioxane andtetrahydrofuran. For preference, ethyl acetate or methyl acetate isused.

The process itself may be carried out by mixing the methylol compoundwith the hexaalkyldisilazane and, where used, the acid catalyst and/ ora solvent and heating the mixture to the reaction temperature, whenliberation of ammonia or of the amine from which the hexaalkyldisilazaneis derived takes place. After the reaction is complete, the product isWorked up by distillation or crystallisation, alternatively, thereaction may be carried out by adding the methylol compound to the otherreactants either continuously or discontinuously.

A preferred method of preparing the N-methylolsilyl ethers according tothe invention consists in reacting the N-methylol compounds withhexamethyldisilazane in a molar ratio of 1:1.1-2 in the presence ofcatalytic quantities of (NH SO at 40 to 80 C. with the exclusion ofmoisture and with stirring. After only a short time the reaction becomesevident by vigorous evolution of ammonia. When the evolution of gas hasdied down, stirring is continued for another to minutes and the excesshexamethyldisilazane is drawn off. For many purposes, theN-methylolsilyl ether obtained in this way is sufficiently pure.

Other disilazanes and different proportions of reactants catalysts ororganic solvents may be used and different temperatures may be employed.

If it is desired to prepare the methylolsilyl ethers by reacting alkylmonochlorosilanes with N-methylol compounds, the presence ofstoichiometric quantities of HCl acceptors such as pyridine or othertertiary amines is necessary. The hydrochloride produced in largequantities 4 in this reaction, however, renders working up difiicult andeasily cause undesired side reactions.

These disadvantages can be obviated by the process according to theinvention.

N-methylolsilyl ethers prepared according to the invention are valuableintermediate products for medicaments, textile auxiliary agents andsynthetic resins.

The N-methylolsilyl ethers are capable of reacting with other reactiongroups e.g. hydroxyl groups, carboxyl groups, amino groups, even undermild conditions. Therefore, the N-methylolsilyl ethers are useful formodifying polymers and polycondensation products containing theabovesaid groups, e.g. for hydrophobing cellulose and partial celluloseesters as well as for crease-proofing cotton.

Bior polyfunctional N-methylolsilyl ethers as well as the disilyl etherof N,N-dimethylol adipic acid diamide react with hydroxylgroup-containing macromolecules with cross-linking. Therefore, they canbe used as crosslinking agents in lacquer binders having incorporatedhydroxyl groups.

EXAMPLE 1 10 g. (0.112 mol) of N-methylolacetamide, 9 g. (0.056 mol) ofhexamethyldisilazane and 0.01 g. of sulphuric acid are heated to 70 to75 C. with stirring and exclusion of moisture. After a short time, briskliberation of ammonia begins and this is complete after about 10minutes. The solution is diluted with about ml. of petroleum ether,filtered, and the solvent is drawn off. The residue is fractionatedusing an oil pump.

Yield: 13 g. (0.086 mol)=71.8% by weight of the theoretical. B.P. 0.160-61 C. d =0.962 n =1.4361. C H O NSi calculated (percent): C, 44.69;H, 9.38; N, 8.69; Si, 17.42; (161.248). Found (percent): C, 44.42; H,9.17; N, 9.02, Si 17.10.

EXAMPLE 2 In a manner analogous to Example 1, 9 g. (0.044 mol) ofN,N-dimethylol-adipic acid diamide are reacted with 17.1 g. (0.1 mol) ofhexamethyldisilazane. About 35 ml. of benzene are added to the resultingsolution, the solution is filtered and the solvent is drawn off. Theresidue is recrystallised from' methyl acetate.

Yield: 10 g. (0.0287 mol)=65.4% by Weight of theoretical. Melting point:7575.5 C. C H O N Si calculated (percent): C, 48.24; H, 9.25; N, 8.04;Si, 16.12 (348.606). Found (percent): C, 48.52; H, 8.93; N, 8.24; Si,16.15.

EXAMPLE 3 29.5 g. (0.2 mol) of N,N-dimethylolurea, 40 g. (10.25 mol) ofhexamethyldisilazane, 29 g. of dimethylsulphoxide and 0.1 g. of (NH SOare heated to to C. with stirring and exclusion of moisture. After ashort time, brisk evolution of ammonia begins and this is complete afterabout 10 minutes. The solution is diluted with about 50 ml. of petroleumether, filtered, and cooled with ice. The precipitated product isseparated by suction filtration, dried, and recrystallised from ligroin.Yield: 44 g. (0.1505 mol)=% by weight of theoretical. Melting point: 158C. (with decomposition).

EXAMPLE 4 In a manner analogous to Example 1, 24 g. (0.202 mol) ofN-methylol-carbamic acid ethyl ester and 18.5 g. (0.115 mol) ofhexamethyldisilazane are reacted at 55 to 50 C. in the presence of 0.01g. of sulphuric acid (conc.). When the reaction is complete, the productis removed by suction filtration and fractioned using an oil pump.

Yield: 20 g. (0.091 mol):45.5% by weight of theoretical. B.P. 04 5052 C.d =0.9890 n =l.4286 C H O NSi, molecular weight 191.311. Calculated(percent):nC, 43.95; H, 8.95; N, 7.32; Si, 14.68. Found (percent): C,44.16; H, 8.71; N, 7.16; Si, 14.27.

EXAMPLE 5 In a manner analogous to Example 1, 6.5 g. (0.05 mol) ofN-methyl-sorbic acid amide and 5 g. (0.031 mol) of hexamethyldisilazaneare reacted together in the presence of 0.01 g. of sulphuric acid(cone). When the reaction is complete, 20 ml. of petroleum ether areadded, the reaction mixture is filtered, the filtrate is cooled and theprecipitated product is separated by suction filtration and dried.Yield: 5 g. (0.0228 mol):47.5% by weight of the theoretical. Meltingpoint: 79-80 C.

C H NO Si calculated (percent): C, 56.29; Si, 13.16; (213.36). Found(percent): C, 56.29; Si, 13.00.

EXAMPLE 6 In a manner analogous to Example 1, 5 g. (0.0226 mol) ofN-methylol-phthalimide and 2 g. (0.0124 mol) of hexamethyldisilazane and0.1 g. of NH Cl are boiled under reflux at 120-130 C. When the reactionis complete, petroleum ether is added, the reaction mixture is filtered,the filtrate is cooled with ice, and the precipitated product isseparated by suction filtration and dried.

Yield: 3.5 g. (0.01408 mol)=62% by weight of theoretical. Melting point:6-263 C. C H O NSi calculated (percent): C, 57.71; H, 6.06; N, 5.62; Si,11.26; (249.35). Found (percent): C, 57.79; H, 5.95; N, 5.70; Si, 10.91.

EXAMPLE 7 g. (0.198 mol) of N-methylolacrylamide, 18 g. (0.112 mol) ofhexamethyldisilazane, ml. of methyl acetate, 0.1 g. of (NH SO, and 0.01g. of phenothiazine are reacted together at to C. in a manner analogousto Example 1. The solvent is evaporated 011 and the residue is distilledusing an oil pump.

Yield: 29.5 g. (0.17 m0l):=85% theoretical. BR 02 78-79 C. d =0.9800 n=1.4582 C H O NSi calculated (percent): C, 48.52; H, 8.72; N, 8.08; Si,16.21; (173.295). Found (percent): C, 48.53; H, 8.53; N, 8.34; Si,16.02.

EXAMPLE 8 In a manner analogous to Example 7, 300 g. (2.6 mol) ofN-methylol-methacrylic acid amide, 240 g. (1.5 mol) ofhexamethyldisilazane, and 0.1 g. of (NH SO are reacted at 40 C. in thepresence of 250 ml. of ethyl acetate and 0.01 g. of phenothiazine andWorked up.

Yield: 469 g. (2.5 mol)=96% by weight of theoretical. HP. 02 7779 C.Melting point: 3132 C. C H O NSi calculated (percent): C, 51.26; H,9.16; N, 7.48; Si, 14.95; (187.20). Found (percent): C, 50.66; H, 9.29;N, 7.46; Si, 14.73.

If 50 g. (0.045 mol) of N-methylol-methacrylic acid amide and g. (0.26mol) of N-methyl-hexamethyldisilazane are reacted under the conditionsof Example 8 there are obtained 61 g. (0.33 mol)=73% by weight ofmethacrylic acid amide-N-methylol-trimethylsilyl ether. Melting point:31-32 C.

EXAMPLE 9 In a manner analogous to Example 1, 3 g. (0.015 mol) ofN-methylol-p-toluenesulphonic acid amide and 1.75 g. (0.008 mol) ofhexamethyldisilazane are reacted together at 75 to 80 C. in the presenceof 0.01 g. of sulphuric acid (cone). When the reaction is complete,petroleum ether is added and the reaction mixture is filtered.

The filtrate is cooled and the precipitated product is separated bysuction filtration and recrystallised.

Yield: 3 g. (0.011 mol)=73.5% by weight of theoretical. Melting point:70.571.5 C. C H O NSi calculated (percent): C, 48.32; H, 7.00; N, 0.12;Si, 10.27; (273.417). Found (percent): C, 48.48; H, 6.45; N, 5.30; Si,10.21.

by weight of EXAMPLE 10 In a manner analogous to Example 1, 23 g. (0.17mol) of N-methylol-carbamic acid allyl ester in 15 g. of ethyl acetateare reacted with 15 g. (0.09 mol) of hexamethyl disilazane at 85 C.within 20 minutes and worked up.

Yield: 25 g. (0.12 mol) =71% by weight of theoretical. B.P. 58-61 0. 111.4452 1, 1.0206 C H NO Si calculated (percent): C, 47.26; H, 8.43; Si,13.82; (203.322). Found (percent): C, 47.46; H, 8.39; Si, 13.46.

EXAMPLE 11 21.5 g. (approximately 0.1 mol) of a methylolmelarninecompound prepared from formaldehyde and melamine and containing aboutthree methylol groups were dissolved in 50 ml. of dimethylsulphoxide andreacted with 30 g. (0.19 mol) of hexamethyldisilazane at 6070 C. within15 minutes. The solvent was drawn off and the residue was dissolved inethyl acetate and precipitated from petroleum ether.

Yield: 34 g. (0.079 mol)=79% by weight of the theoretical.

The product had an Si content of 18.4%, which corresponds to a degree ofsubstitution of the methylol groups of EXAMPLE 12 In a manner analogousto Example 1, 15 g. (0.1 mol) of nicotinic acid amide are reacted with12 g. (0.06 mol) of hexamethyldisilazane at about 80 C. within 10minutes. The product was recrystallised from petroleum ether.

Yield: 17 g. (0.07 mol)=76% by Weight of the theoretical. Melting point:7474.5 C. C H N O Si calculated (percent): C, 53.54; N, 12.49; Si,12.52; (224.344). Found (percent): C, 54.10; N, 12.40; Si, 12.60.

EXAMPLE 13 In a manner analogous to Example 1, 10 g. (0.064 mol) ofN-methylolhexahydrobenzoic acid amide are reacted with 9 g. (0.05 mol)of hexamethyldisilazane at 60 C.

Yield: 10.5 g. (0.044 mol) =69% by weight of theoretical. Melting point:7172 C. C H NO Si calculated (percent): C, 57.99; H, 10.57; N, 6.13;(228.411). Found (percent): C, 57.25; H, 9.84; N, 6.38.

EXAMPLE 14 In a manner analogous to Example 1, 13 g. (0.1 mol) ofN-methyl-p-chlorobenzoic acid amide are reacted With 12 g. (0.75 mol) ofhexamethyldisilazane at C.

Yield: 11 g. (0.043 mol)=43% by Weight of theoretical. Melting point:9091 C. C H ClNO Si calculated (percent): C, 51.34; H, 6.27; N, 5.44;(257.804). Found (percent): C, 51.52; H, 6.24; N, 5.42.

EXAMPLE 15 In a manner analogous to Example 1, 16.5 g. (0.1 mol) ofN-methylolphenylacetic acid amide are reacted with 12 g. (0.075 mol) ofhexamethyldisilazane at 60-70 C.

Yield: 12 g. (0.51 mol):51% by weight of theoretical. Melting point:4152 C. C H NO Si calculated .(percent): C, 60.73; H, 8.11; N, 5.90;(237.364). Found (jercent): C,60.69; H, 7.75; N, 6.10.

EXAMPLE 16 10 parts by weight of N-trimethyl siloxymethylmethacrylamide, 30 parts by weight of methyl methacrylate are mixed with45 parts by weight of xylene. After addition of 0.4 parts by Weight ofazodiisobutyrodinitrile and 0.3 parts by weight ofditerL-dOdecylmercaptan as regulator polymerization 'was carried out at70 C. during 6.5 hours. The copolymer obtained has a relative viscosityof 1.1953 measured With an Oswald Viscosimeter at 25 C. and at aconcentration of 10 g./litre in benzene.

Demonstration of convention of the soluble copolymer into insolublecross-linked product: 0.22 ml. of a 4 n-H SO solution is added to 20 g.of a 25% by weight so ution in xylene/butanol (11:1) of the copolymerobtained. The mixture becomes cloudy after only 10 min- 7 utes, agel-like product being formed, accompanied by cross-linking. A film ofthe copolymer which is stoved for 30 minutes at 150 C. is insoluble inxylene and has a gel-content of almost 100%.

What is claimed is: 1. A compound of the formula \N rNm N/ I R N N Rwherein from one to six of said R substituents are of the formulawherein R is lower alkyl and when there are less than six of saidsubstituents of said formula, the balance of the R substituents arehydrogen, alkyl having 1 to 4 carbon atoms, alkenyl having 2 to 6 carbonatoms or butadiene (1,3)-yl with but one of said alkyl, alkenyl andbutadiene-(l,3)-yl substituents per exocyclic nitrogen atom.

2. A compound of claim 1 wherein R is methyl.

3. A compound of claim 1 wherein six of said R substituents are of thestated formula.

4. The compound of claim 3 wherein R is methyl.

5. A compound of claim 1 wherein less than six of said R substituentsare of the stated formula and the balance thereof are hydrogen.

6. A compound of claim 5 wherein R is hydrogen.

References Cited UNITED STATES PATENTS 8/1960 Bailey et al. 260249.6X3/1966 Watt 260249.6X

US. Cl. X.R.

